AgendaWhat is RFID? Why is it interesting?Basic Components How it works Variety of solutionsDesign issues Technology perspective Human perspective (today’s readings)
Types of Radio Frequency Identification: Passive and Active RFID is a wireless means of communicating data at interesting locations Contrast with WLAN or WPAN
A Passive RFID system consists of:RFID tagsRFID readerMiddleware.The identification of the RFID tag takes place bythe reader over the wireless medium or air
• Logistics such as in manufacturing,warehousing, and distribution systems;• Security in libraries and bookstores,passports, and airports;• Transportation in automatic vehicleidentification, electronic toll collection, andelectronic vehicle registration.
Middleware is the software component between the RFID reader hardware and RFID application software.RFID middleware :filters, formats, and converts low-level RFIDhardware communication with the tags intousable event information, so that the datacan be processed by a software application.
In an RFID system, middleware translates machineinformation into tag event information, like:“reader reads a tag.” This information can include someother useful parts depending on the specific readermodel used, such as tag ID, zone ID, and time stamp.The reader generates huge amounts of such eventinformation.
Why is RFID interesting?Cost-effective means of tracking assetsBecoming price competitiveReadings for today motivate different kinds of ubicomp applications for practical sensing.
Basic ComponentsEvery RFID system is composed of: Tags/transponders Powered (active) or unpowered (passive) Readers/interrogators Antenna attached to reader
How it works(active propagation coupling)Tags have Microprocessor + memory Metal coil (antenna) separate power sourceCommunication between reader antenna and tag is similar to wireless LAN communication.
How it works( passive inductive coupling)Tags have Microprocessor + memory Metal coil (antenna) No separate power sourceReader’s antenna generates a magnetic field, inducing a voltage in the tag’s antenna, giving it energy to perform a “return” communication, modulated over carrier frequency.
Different kinds of RFIDFrequency range for carrier signal Regulated differently around the worldLow 100-500 kHzMedium 10-15 MHz
Design Issues: TechnologicalRange Shorter with passive vs. active Shorter with lower carrier freq Affected by antenna and surrounding environment (water, humans) Affected by relative orientation of antenna-tag Usually do not require line of sight (except for high freq)
Other Technological IssuesRead and/or WriteCost Low & mid are relatively inexpensive Especially on a per-read basisHealth ??, but looks to be OK because of RF regulation
Design Issues: Human PerspectiveRFID looks promising for implicit interaction.It is a fairly robust sensing technology.Design challenge Getting “reads” when and where you want them without requiring awkward interactions by humans
Design Communicate movement trendsTechnology Room-level location
Room-level location with RFIDCustom floor mats:To Detect theentrance